Most US taxpayers overlook one critical factor, which can quickly turn a manageable tax bill into a financial headache: interest. If you do not pay your federal taxes on time, the IRS will start charging interest immediately, and unlike penalties, interest is rarely waived or reduced.
What is worse, the longer your balance remains unpaid, the faster the amount you owe grows. Let us show you the steps to avoid watching your tax bill balloon out of control.
IRS Interest Rates for Payment Plans
The IRS starts to charge interest on your account the very first day that you are late and have not paid the entire tax debt. Interest is applied to the remaining balance and continues to accrue until the balance is paid off. Even if you set up a payment plan, interest continues to accrue on your account.
Moreover, the IRS interest rate compounds daily, meaning it is assessed to your account daily. Therefore, even small balances can increase significantly over time.
What are the IRS interest rates for 2026?
For the 2026 tax year (as of the first quarter beginning January 1, 2026), IRS interest rates are:
- 7% for individual tax overpayments and underpayments, compounded daily,
- 6% for corporate overpayments,
- 4.5% on the portion of a corporate overpayment exceeding $10,000,
- 7% for corporate underpayments, and
- 9% for large corporate underpayments.
These rates are set quarterly by the IRS based on federal short‑term rates plus statutory add‑ons.
How Does the IRS Calculate Interest on Unpaid Taxes?
The IRS interest on unpaid taxes is compounded daily, meaning it adds up on both the original tax owed and any previously accrued interest. This continues until the entire balance, including interest, is paid off.
In rare situations, such as if the IRS made a mistake, interest may be reduced or waived. However, interest typically cannot be waived just because you missed a payment.
How Does the IRS Calculate Your Monthly Payment with Interest?
This step-by-step method gives you an idea of what to expect, so you are financially prepared when making monthly payments on your debt.
Step 1: Determine the Base Monthly Payment
Start by calculating your base monthly payment, which is the amount you need to pay to clear your debt in a certain number of months. For example, if you owe $10,000 and plan to pay it off in 60 months (five years), you divide $10,000 by 60. In this case, your base payment would be about $166.67.
Step 2: Calculate the Interest
As of early 2026, the IRS annual interest rate on unpaid taxes is 7%, compounded daily.
To estimate monthly interest:
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Multiply your balance by the interest rate:
$10,000 × 0.07 = $700 annually -
Divide by 12 to get the monthly interest:
$700 ÷ 12 = $58.33
Step 3: Add the Base Payment and Monthly Interest
Now combine the base payment and estimated interest: $166.67 + $58.33 = $225.00
This is your estimated monthly payment with interest.
Step 4: Adjust for Penalties (If Any)
If the IRS applies a late-payment penalty, such as 0.25% monthly, you’ll need to factor that in.
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Total annual rate becomes 7.25%
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$10,000 × 0.0725 = $725 annually -
$725 ÷ 12 = $60.42 monthly interest
Total monthly payment: $166.67 + $60.42 = $227.09
Important Notes:
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IRS interest is compounded daily, so actual interest may be slightly higher over time.
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Interest declines as you pay down the principal, so monthly totals will gradually decrease.
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This method provides a useful estimate, but your actual IRS payment plan may vary depending on penalties, fees, and compounding.
IRS Interest Rates and Penalties
The IRS also imposes penalties on unpaid taxes, which can increase the overall amount owed. The late payment penalty, the most common, is typically 0.5% of the unpaid taxes for each month the payment is late, up to a maximum of 25%.
The late filing penalty is more severe. If you fail to file your tax return on time, the penalty is 5% of the unpaid taxes for each month the return is late, up to a maximum of 25%.
If both the late payment and late filing penalties apply, the IRS reduces the late filing penalty by the amount of the late payment penalty to avoid double penalties in the same month.
By resolving tax debts sooner rather than later, you can minimize these extra charges and avoid further financial strain. Otherwise, the penalties continue to accrue until the debt is paid in full or an installment agreement is set up.
How to Avoid Accumulating Too Much Interest
The longer you take to pay off your debt, the more interest accrues, so pay off the debt faster. If possible, make larger or additional payments each month to decrease the principal faster. This strategy will help you lower the total interest paid over time and clear the debt sooner, reducing the overall financial burden.
Moreover, you may benefit from penalty abatement, which reduces or eliminates penalties. However, you should show reasonable cause for why you fall behind on payments. Lastly, if you set up a payment plan, the failure-to-pay penalty drops to 0.25% per month, instead of the higher rate you would face without one. This reduction in penalty helps minimize the overall amount you owe and limits the additional interest that can accumulate.
Lastly
Even if you set up a payment plan, interest will still add up as long as you owe the IRS. However, by making regular payments, you can reduce the amount of interest you pay since you will be lowering the principal balance.
If you are looking for a solution beyond a payment plan or installment agreement for your tax debt, Precision Tax Relief experts are here to help you find the right option. Reach out today for your free initial consultation.
Frequently Asked Questions
Typically, the IRS starts charging interest as soon as taxes become overdue. Even if you request an extension, interest will continue to accrue on any unpaid taxes starting the day after the original filing deadline (usually April 15). Interest will keep accumulating until the balance is paid in full.
Even if you file an extension, interest will continue to accrue on any unpaid taxes during this period.
Yes, even if you set up a payment plan, interest continues to accrue daily on the remaining balance and is compounded daily until the entire debt is paid of
The IRS interest rates for unpaid taxes are determined based on the federal short-term interest rate and are updated quarterly. These rates can vary from year to year.
You can request a refund.
There are many tools available online; you can use one of them.